Question: Expand and combine like terms. $(4+3c^5)(4-3c^5)=$
Answer: We can expand this expression like any product of two binomials. However, this expression has a special form that makes it easier to expand. This is the "difference of squares" form (where $P$ and $Q$ can be any monomial): $(P+Q)(P-Q)=P^2-Q^2$ $\begin{aligned} &\phantom{=}(4+3c^5)(4-3c^5) \\\\ &=(4)^2-\left(3c^5\right)^2 \\\\ &=16-9c^{10} \end{aligned}$